Distinguish between the terms “harmonisation” and “convergence” as they apply to accounting standards

Just start with thinking about the fact that prior to the introduction of IFRS, most nations had their own national accounting standards.
The ideal position to move to from this point - where there would be no differences at all in the accounting standards in place in every country - is FULL CONVERSION - in this case each nation totally removes its old, national standards and adopts only IFR standards - and nothing else. This is the accounting standard setters ideal as every company's performance could be very fairly compared as they would all be using exactly the same rules (or very close to this) for the recording and reporting of their key business transactions.
However, the reality is, as we saw during the semester with the EU, there have been a lot of concessions made to powerful countries - such as Germany and Japan and China - which allows them to only "harmonise". Under this guideline, nations simply and gradually change/modify one standard at a time until they have all their old, relevant accounting standards aligned or consistent with any matching IFRS - e.g. there is an international standard on segments - IFRS 8 as we have seen - each nation that is "harmonising" only will modify their existing segment reporting standard to be as closely aligned with the IFRS 8 std. as possible - but differences will and do occur as we have seen as a result of legal rules etc. that operate within each nation.
Once all the national accounting standards are aligned with matching IFR standards - then, for the business transactions covered by the IFR standard, there is a form of convergence - i.e. all the nations should be adopting the same or very similar, global rules for that business transaction.
However, this convergence process is flawed in that nations such as the US retain a range of their existing national standards - which listed companies have to comply with as well as the IFRS - i.e. THEY HAVE NOT FULLY CONVERTED TO COMPLYING ONLY WITH IFRS - this is very confusing to the market - as US company reports are complying with over 300 accounting standards related to a wide range of business transactions while Australian companies by comparison ONLY HAVE the IFRS in place and nothing else.
Where there is doubt and "opaque" practices, mismanagement and fraud can occur and the investment risk in those countries increases as a result.
Thus: Harmonisation is the slow process of modifying existing national accounting standards to be more aligned, one by one, with any matching IFRS - it leads to inconsistent accounting rules across countries as the alignment is not perfect.